Polk Audio Signa S4 Atmos Soundbar image 2

Polk Audio Signa S4 Review

Most entry-level Soundbars on the market that support 3D audio use a “simulated” output method, which uses audio processing to give users a sense of overhead sound. The advantage of this is that no additional hardware is required and it is simple and convenient, but the downside is that the effect is sometimes not obvious.

Polk Audio Signa S4 Atmos Soundbar image

The latest Polk Audio Signa S4 soundbar adds two upward-firing units to the main Soundbar, providing real Dolby Atmos 3.1.2 channel output. The accompanying subwoofer supports Bluetooth connectivity, which is extremely convenient for building a living room home theater, at least users don’t have to worry about wiring.

Polk Audio Signa S4 Atmos Soundbar subwoofer image


Although the Signa series is an entry-level series of Polk Audio Soundbars, it is larger than the Signa S2, but Signa S2 is still slim in thickness and lightweight. Therefore, whether it is placed on a TV cabinet or wall-mounted, users do not have to worry about space issues.

Signa S4 is covered with a deep grey textile fabric, giving the product a more homely feel. It feels smooth and flowing, with no burrs. The metal logo is located in the lower right corner of the soundbar. In addition, there are no other unnecessary decorations on the soundbar, and the overall design style is simple.

Polk Audio Signa S4 Soundbar

The Signa S4 is the first to introduce independent overhead sound channel units. The main unit of the Soundbar has two 2.6-inch upward-firing units that output full-frequency units of overhead sound through overhead reflection. This is unique among Soundbars in this price range.

The front also has independent left, center, and right channel outputs, with 1-inch tweeters and 40mm x 120mm mid-range units on the left and right channels, and a 1-inch full-frequency unit on the center channel. Combined with the wireless subwoofer with a 5.9-inch woofer, it forms a true Dolby Atmos 3.1.2 channel Soundbar system.

The Soundbar itself has a longer design, but its 60mm height is low and thin enough not to block the TV screen. In addition, it supports wall mounting and is flexible in placement.

Connection and setup are also very convenient. The HDMI port on the Soundbar supports eARC and can output Dolby Atmos 3D sound through feedback. It is especially suitable for recent smart TVs. When the TV installs streaming apps such as Netflix and Disney+ and plays films with surround sound or even Dolby Atmos, the Soundbar can output more shocking sound through the simple HDMI connection, which can bring considerable sound enhancement.

Polk Audio Signa S4 Atmos Soundbar design

The Signa S4 also has fiber and 3.5mm audio (AUX) input, which is no problem for connecting additional equipment such as game consoles. In terms of wireless connection, it is equipped with Bluetooth 5.0, which is convenient for connecting phones to play music.

The remote control provides various source selections and sound settings, with three sound modes: Movie, Music, and Night. The 3-level Voice Adjust setting is convenient for adjusting the voice output of films as needed, and the Bass Adjust can independently adjust the low-frequency effect. The settings are very simple and easy to understand and are also very practical.

There is also a wireless subwoofer paired with the main speaker, probably to accommodate the use of small and medium-sized living rooms. Its body design is also slim, and its size can be described as “mini” compared to custom home theater subwoofers.

Polk Audio Signa S4 Atmos Soundbar

Users can place it side by side with the speaker or choose to put it behind the sofa. Although the manual recommends that the distance between the subwoofer and the soundbar should not exceed 10m, to achieve better results, theoretically, the closer the distance between the two speakers, the better.

There is no difficulty in installation. The Signa S4 comes with an HDMI cable and a digital fiber optic cable. Users only need to connect the soundbar and subwoofer to the power supply and use the HDMI cable (or fiber optic cable) to connect to the TV to use it.

The Controller

The Signa S4 also comes with a remote control. On the remote control, we can have a general understanding of the functions supported by the Signa S4. For example, it supports three types of inputs: fiber optic, HDMI, and Bluetooth. In different modes, the indicator light in front of the soundbar will also have corresponding indications.

Polk Audio Signa S4 Atmos Soundbar controller

The lower six buttons on the remote control are primarily used to easily switch between the six preset sound modes that Polk Audio has set. The first three are “Movie”, “Music”, and “Night Mode”, while the other three correspond to the “VoiceAdjust” function. This function, which was also carried over from the previous generation, can improve the clarity of the dialogue in movies without changing the volume of the background music. The three numbers represent an increase in the effect.

Sound Performance

Signa S4 has two additional upward-firing units, in addition to the ones on the Signa S2, creating a seven-unit array design that can create a 5.1.2 virtual three-dimensional immersive sound effect. It has also received Dolby Atmos certification. The purpose of the upward-firing units is to enhance the 3D sense of sound, allowing viewers to feel a sense of realism as if an airplane were flying overhead.

Polk Audio Signa S4 Atmos Soundbar button

If you are looking for a truly immersive, stunning listening experience, the Signa S4 will certainly deliver an exceptional 3D surround sound experience. However, if you simply want to enhance your normal movie-watching sound, the more affordably priced Signa S2 should be sufficient.

The Signa S4 performs very well in terms of vocals, bass, and overhead sound effects. The vocals are particularly three-dimensional and prominent, and it is hard to believe that such a thin soundbar can produce such an effect. In fact, the Signa S4 already has this performance in its standard vocal mode (VoiceAdjust at the lowest setting).

Watching Netflix’s “The Red Notice” with a lot of dialogue, the vocal analysis is high and the authenticity is also very good, suitable for daily TV and drama. In addition, the clear vocals paired with Bluetooth listening to music also have the advantage of a longer distance between the left and right units of the soundbar, which can provide a somewhat three-dimensional position for playing music.

And when watching the action scene in Disney+’s “Hawkeye,” the sense of direction of the arrow is very clear. Although the sound field can only cover the front half of the space, the combination of the soundbar and the subwoofer is enough for the task. Combined with the overhead sound effects, it can create a somewhat spacious sense of space.

The ceiling sound channel of the Signa S4 indeed has a good effect, especially for some sound effects such as thunder, archery, and planes flying over, which can provide better positioning than simulated 3D sound effects.

The sound imaging will also be clearer, without the “blended” and blurry sound effects from the top. However, it should be noted that the reflection method of ceiling sound has some requirements for the reflection angle and listening position, and the best effect can only be achieved by aligning the reflection position correctly.

The accompanying subwoofer of the Polk Soundbar has always performed well, and this time is no exception. The 150mm downward-firing woofer has a good sense of energy, and although it does not dive very deeply, it has sufficient volume and impact. It can cope with spaces of around 150 feet, and the downward-firing unit design provides a very good sense of envelopment. If the listening space is a little smaller, you may even need to lower the bass output a bit.

Polk Audio Signa S4 Atmos Soundbar image 0


The Polk Audio Soundbar series has always been of high quality, and the Signa S4 has introduced upward-firing speakers to provide a more complete Dolby Atmos 3D effect. Compared to most entry-level Soundbars that support simulated 3D sound, the Signa S4 provides more detailed overhead sound imaging, with clearer positioning and directional sense.

With its distinctive, powerful bass and prominent vocals, the Signa S4 is especially suitable for users who subscribe to streaming platforms such as Netflix and Disney+ and want to upgrade their sound in a simple and convenient way. It is also very affordable and can be considered the best choice among entry-level Soundbars at the same price point. It performs well in all aspects, including movies, TV shows, and music.

If you’re looking to upgrade your home entertainment experience, the Signa S4 is a fantastic choice. With its impressive three-dimensional sound, clear vocal reproduction, and strong bass performance, it’ll bring your movies, TV shows, and music to life like never before.